PROJECT SUMMARY/ ABSTRACT Permanent childhood hearing loss, which occurs in 1-2/1000 live-births, has negative impacts on children's lives incurring high societal costs. Universal newborn hearing screening (UNHS) enables early detection of hearing loss and intervention, with the goal of improving long-term outcomes at a population level. Despite widespread adoption of UNHS, serious evidence gaps remain. The effectiveness of early intervention for improving long-term outcomes is uncertain, the cost-effectiveness is unproven, and the impact of device fitting on outcomes of children with unilateral hearing loss is unknown. By capitalizing on a unique environment in Australia where children receive uniform hearing services from a single provider (Australian Hearing, AH), but had differential access to UNHS during a narrow time window, the research team commenced the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study in 2005. Through NIH support, a population-based cohort of 450 children with bilateral hearing loss (53% fitted with hearing aids before age 6 months) have been enrolled, and their outcomes have been measured prospectively over 10 years. The 5-year data revealed that the earlier children received hearing-aid fitting or cochlear implantation, the better the language outcomes. Benefits were greater for those with more severe hearing loss. Would these early benefits extend to later educational attainment, psychosocial well-being, and quality of life? Is early intervention cost- effectiveness in the long term? Further, does early intervention improve outcomes of children born with unilateral hearing loss? As a non-target condition detected via UNHS, there is clinical equipoise about management because evidence is lacking. Supported by NIH, the Children with Unilateral Hearing Loss (CUHL) study enrolled 179 children, ~50% of whom were randomly assigned to fitting of devices after diagnosis. This application draws on the assembled LOCHI and CUHL cohorts. The Aims are to: (1) determine the long-term effectiveness of early intervention by measuring outcomes of the LOCHI cohort at 16 years of age; (2) determine the cost-effectiveness by performing an economic evaluation using data on outcomes and healthcare resource use to be collected from the LOCHI cohort; and (3) determine how fitting and use of hearing device influence language outcomes of children with unilateral hearing loss by evaluating the CUHL cohort at 3 and 5 years of age. All data and a range of predictors will be evaluated in multiple regression analyses and structural equation modelling. As the research arm of AH, we will minimise loss to follow-up by maintaining contact via the AH service provision network. Accomplishing the aims will a) provide the much-needed evidence to guide clinical best-practice management of children across the entire spectrum of hearing loss, including unilateral hearing loss; and b) demonstrate the cost-effectiveness of UNHS and early intervention to guide policy decisions.